You can find them on sparkfun.com, look up Lilypad LEDs.... Lilypad is a wearable electronics brand. Here's a google search that has several options for LEDshttps://www.google.com/search?q=lilypad+leds&rlz=1C1CHFX_enUS590US590&oq=lilypad+leds&aqs=chrome..69i57j0l3.7262j0j7&sourceid=chrome&ie=UTF-8

Finished this a few weeks ago, and thought I would share because it turned out great! I gave him as a present to my boyfriend who loved Calvin and Hobbes and he was really touched. Thanks so much for sharing your pattern!